The major goal of the physiology Core of the Scripps NeuroAIDS Preclinical Studies (SNAPS), CSPAR, is to continue to provide neurophysiological assessment of the development and full expression of AIDS-related functional pathology employing a variety of existing animal models with clinical phenotypes relevant for AIDS dementia. This Core services will include continued evaluation of current primate and feline models infected with the analogous lentivirus (SIV and FIV, respectively) as well as assessment of existing and new mouse models representing molecularly engineered phenotypes relevant for HIV-1 infection. Indeed, is our goal to not only provide an improved broader spectrum analysis of functional disease progression, but also to recruit and provide this sort of expanded assess to new SNAPS P.I. collaborators, who will further enrich our assessment potential. To accomplish this role, the physiology Core is subdivided into 4 separate but interacting "TEAMS", that function to carry out specific scientific analyses in the Core. The three service units are: 1. The in vivo physiology assessment team; 2. The in vitro physiology assessment team; 3. The radiotelemetry team, and 4. The evoked potential team. The organization model is diagramed in the body of the Core text. These four functional units currently have well established scientific teams headed by the P.I.'s of the Core and supported by highly trained research assistants daily employing the methodologies proposed as the assessment tools. A key strength of this SNAP Core is that the individual research teams have over 10 years of experiences using these research tools to assess AIDS-related functional changes. We also propose an administrative research unit headed by Drs. Henricksen and Siggins that will investigate new neurophysiological tools that could be applied to the Core scientific scope. The physiology Core is directed by planning, prioritization, budget decisions, and data evaluation. The Core Co-P.I.., Dr. George Siggins, will primarily concentrate his responsibilities within in vitro physiology UNIT for which he has requested 10% effort. In addition, Dr. Siggins will serve as a senior advisory for individual Core units where he shares expertise. Logistically, Drs. Henricksen and Siggins occupy adjacent laboratories in the Blake building of TSRI.